A forest of hypotheses

Falling in love with a single theory can cut off fruitful avenues of enquiry. Here’s how to keep your mind open.

The clamour in a Panamanian rainforest is deafening to human ears: bugs shriek, birds sing and bats screech throughout the humid night. To avoid attracting predators, male katydids (Tettigoniidae) trill out short, infrequent mating calls less than a second long.

Postdoc Laurel Symes, who studies sensory perception and decision-making at Dartmouth College in Hanover, New Hampshire, wants to understand how female katydids find their mates. She first thought they must have highly sensitive hearing. But she juggles other ideas at the same time: maybe katydids always meet up on a certain type of host plant, have neural mechanisms that filter out background noise or use another trick entirely.

These aren’t just idle musings: Symes’s collection of hypotheses is an integral part of her research. The approach helps her to home in on answers and avoid investment in a sole idea — a common tendency in science that can lead to trouble. History contains numerous examples of scientists who missed important clues because they clung too tightly to a favourite hypothesis. One way to avoid this fate is to consider many potential hypotheses.